Curt schuiiein



Patented Mar. 26 1940 warren s tar-as TREATMENT OF DRIVING BELTS CurtSchiilcin, Bopfingen, Wurttemberg, Germany N Drawing. Application June8, 1938, Serial No. 212,597. In Germany August 27, 1935 "7 Claims.

Belts of leather, balata, jute and the like after being in use for ashort time become smooth, so that they easily slip on the belt pulleysand a loss in power results.

In order to overcome this disadvantage the most varied agents havealready been proposed and employed, by means of which greater adhesivepower has been imparted to the belts, but which have reduced the life ofthe belts. Conversely the most varied belt preservatives have been usedfor increasing their life, but these in general have reduced theadhesive power.

The present invention concerns a coating material for treating drivingbelts, which consists of a specially prepared oil mixture, and also to aprocess for producing the same. The material consists of a viscous,sticky mass, obtained byv heating a mixture of drying oil and castor oilfor several hours at temperatures of from 250 C. to

During theheating operation partial polymerisation of the drying oil andchemical conversion of the castor oil take place. isation of the dryingoil, such as linseed 'oil or wood oil, requires prolonged heating totemperatures above 250 C. It may be promoted by adding siccatives, .forexample cobalt and manganese resinates; when using these, however, theheat treatment must be very exactly controlled. In any event the dryingoil must be prevented from passing over into the solid resinouscondition and as a precautionary measure the polymerisation should beinterrupted before this stage is reached.

With regard to the castor oil, conversion of the ricinoleic acidcontained therein into ricinic acid (octadekadien-acid) apparently takesplace on heating to above 250 C. and this conversion may be promoted bythe addition of polybasic organic acids, which in turn enables a lowerheating temperature of from 250 C. to 280 C. to be employed. Phthalicacid, maleic acid and succinic acid and the like may for example beemployed as polybasic acids. I

When adding siccatives to the mixture the heating temperature shouldalso be limited to about 280 C.

' The following example serves to illustrate the production of thecoating material for driving belts according to this invention:

A mixture of 110 kgms. of castor oil and 65 kgms. of linseed oil isintroduced into a closed The polymervessel and slowly heated up to 340C. This (on. roe-7.5)

temperature is maintained for about 6 hours until appreciablethickeningfof the oil mass has taken place. In the absence of specialadmixtures particular care must be taken to ensure that the temperaturedoes not rise above 340 C. The progress of the reaction is controlled bytaking samples; heating is interrupted when a product is formed which oncooling sets. as a viscous sticky mass. The hot mass isintroduceddirectly into a tightly closed container provided 10 withcooling devices and rapidly cooled therein. The cooled mass is ready foruse. The consistency ,of the product, .which produces high adhesivepowers, as well as its particular chemical nature, which has apreserving 15 effect on the belts, render it particularly suitable foruse as a coating material for driving belts. The material is, easilyapplied and very economical in use; it promotes the. flexibility ofthebe lt, particularly whenmade of leather, and 20 prevents any hardencrusted masses from forming. f

The use of the material according to this invention is attended withparticular advantages with regard to the adhesive powers of the belt.

Such adhesive powers are moreover substantially higher than in the caseof the known heated products obtained from only incompletely dryingoils, such as rapeseed oil, which have been heated at a relatively lowtemperature with inv 30 troduction of air. The contrast however alsoapplies .to rapeseed oil, which has been subjected to heating at thesame temperature as the mixture to be employed according to thisinvention. 1

I claim: 35

1. A coating material for treating driving belts consisting of aviscous, sticky mass obtained from a mixture of drying'oil and castoroil by heating the mixture for several hours to temperatures of from 250C. to 340 C. 40 2. A coating material for treating driving'beltsconsisting of a viscous, sticky mass obtained from a mixture of linseedoil and castor oil by heatingthe mixture for several hours totemperatures of, from 250C; to 340 C. 45

3. A processior the production of a coating material for the treatmentof drivingbelts, characterised in that a mixture of drying oil andcastor oil is converted into a viscous sticky mass by heating forseveral hours to temperatures of from 250 C. to 340 C.

4. A process as claimed in claim '3, wherein a mixture of linseed oiland castor oil is heated for several hours to temperatures of from 250C. to

5. A process as claimed in claim 3, wherein siccatives are added to themixture and the heating is carried through at temperatures of from 250C. to 280 C.

6. A process as claimed in claim 3, wherein polybasic organic acids areadded to the mixture and the heating is carried through at temperaturesof from 250 C. to 280 C.

7. A process as claimed in claim 3, wherein siccatives and polybasicorganic acids are added to the mixture and the heating is carriedthrough at temperatures of from 250 C. to 280 C.

CURT scm'iLEIN.

